Clevidipine is a dihydropyridine calcium channel blocker that reduces blood pressure in a subject to which it is administered. It is characterized as a short-acting, highly selective drug that is typically used in a hospital setting due to its rapid metabolism, exhibiting an initial phase half-life of about one minute and a terminal half-life of approximately 15 minutes. More detailed information on short-acting dihydropyridines can be found in U.S. Pat. No. 5,856,346, the entire disclosure of which is incorporated by reference herein as if set forth in its entirety.
Clevidipine is further characterized by having low solubility in water and moderate to high solubility in lipids. When clevidipine is dissolved in oil-in-water emulsions, it results in better solubility and/or less side effects than when other conventional solution formulations are utilized. Cleviprex® is a clevidipine oil-in-water emulsion formulation approved by the U.S. FDA for intravenous administration in the treatment of acute hypertension, primarily in the emergency room and intensive care unit, and in pre-, peri-, and post-operative settings.
Cleviprex® can support microbial growth since it contains soybean oil and egg yolk phospholipids. Therefore, clevidipine oil-in-water emulsion formulations require strict aseptic technique during handling and administration to avoid microbial contamination that can cause infections among patients. To minimize the possibility of microbial contamination, it is recommended that such formulations be discarded four hours after opening. Such a requirement places a burden on health care providers in that fresh vials of the drug must be continually obtained and set up while the patient is being treated. Accordingly, there exists a need for a stable clevidipine emulsion formulation that is resistant to microbial growth, thereby diminishing the risk of microbial contamination in patients and providing greater ease in handling. Such a formulation would also result in cost savings to the health care providers and patients in decreasing the wastage of clevidipine and reducing the time-consuming efforts involved with manipulation and replacement of vials containing the drug.